Manufacture of paper



Patented Aug. 15, 1933 um'rsp AT- s MANUFACTURE OF PAPER Harold Robert Ration, Andover, Mass, assignor to Raflold Process Corporation, a Corporation of Massachusetts No Drawing. Application December 11, 1930 Serial No. 50l,674

42 Claims.

This invention relates to the manufacture of sized paper filled with alkaline filler.

' The principal object of the invention is to produce sized paper filled with alkaline filler in which the sizing is applied to the paper web.

A further object is to produce. sized paper filled with alkaline filler in which rosin size is employed as the sizing agent.

Other objects and advantages of my invention will become apparent during the course of the following description.

It is well known that the ordinary paper making procedure of sizing paper with rosin size and alum in the beater will not size paper filled with alkaline filler.

In my copending application Serial No. 304,168, filed September 5, 1928, now Patent No. 1,803,643, granted-May 5, 1931, I disclose a method of employing rosin size to size paper filled with alkaline filler, in which method the fibrous suspension containing rosin size which has been precipitated with alum in the beater is treated with .a sizing restoring agent just before the formation of the paper web. In my copendlng appli- 5 cation Serial No. 904,172, filed September 5, 1928,

now Patent 1,803,647, granted May 5, 1931, I disclose a method oi. employing rosin size to size paper filled with alkaline filler, in which'method the fibrous suspension is treated with a s precipitant just before the formation of th paper web.

These procedures, as, is shown in the above applications, entail the addition of a restoring agent or precipitant under conditions favoring 'thetminimizing of the time and/or intimacy of rosin size if the sizing be applied to the web containing alkaline filler instead oi! to the dilute suspension which is,:fed to the web-forming device, and it is this invention which ionfis the subject matter of the present application.

In the practice of my invention a fibrous mix (i. e. a paper making mix) in which alkaline filler is present is fed to the web forniing device of a paper machine, a web is formed, and to this web size and size precipitant isapplied. The

web' is dried and the dried web is finished in any customary manner. The point oi. application, the method or application, the concentration and amounts of size and size precipitant to be applied,"

' Lrate process.

and other necessary or optional details of my process are fully set forth immediately below.

The size and sizeprecipitant. may be applied at any convenient point of the paper machine, either where the web s still in wet condition, e. g. preferably just after press rolls, or at a point where the water has been substantially removed from the web, e. g. preferably just after the driers, or they may optionally be applied to .the paper web subsequent to the paper machine asa sepa- The size and size precipitant may be applied as indicated to the wet or the dryweb but-in case or application .to the dry web, of course, provision mustbe made ifor subsequent removal of the water present in the size and size precipitating solutions, e. g. by passage of the'web over driers or by festoon'ing in a hot atmosphere. In any case, after the applicationoi' the size and size precipitant the web is subjected to 'sufilcient heat for applying liquids to a paper web such as passing the web through successive troughs or-vats containing preferably first the sizing solution and then the size precipitating solution; or by brushes for example rotary brushes, or by contact rolls,

.tothe web by any or the various known methods or by supply boxes on the press rolls, or by spraying or the like. The method of application employed in any given instance is that which is best adapted for use at the particular point at which the sizing is to be applied and should be'chosen with regard to the particular conditions to be met in any given case, all of whichwill be appar ent toone skilled in the art. For example, I have round application by a roll or sprays very convenient methods, especially at a poin subsequent to the first press roll.

The concentration of the solutio to a certain-extent upon the method of employing them am? the point of application. For ap-.

plication by rolls the solutions may be more concentrated, for example 5 per cent. or more, but for immersion or for spraying it is more suitable to have them relatively dilute, conveniently ap proximately 2 to 3 per cent. concentration. The amounts of the two solutions used, while varying. as will be apparent with the grade of paper, its fibrous constituents, the percentage of filler, and

the like, may however, in general, be stated to be depend percentages mentioned in "this paragraph, as

approximately the same as the amounts of size and size precipitant used for the same grade of paper and the same percentage of filler, when sizing clay filled paper in the beater. In general the amount of size used may vary from somewhat under one per cent. up to several per cent. or more, calculated as weight of size on the weight of paper. The precipitant may vary from an amount approximately equal to the size up to 150 per cent. or more of the size used. I do not however limit myself to the concentrations and they may be widely varied according to circumstances as indicated above and still produce satisfactory results.

As the size and precipitant are preferably applied continuously to the web, suitable means for, supplying them to the applying device, e. g. pumps, should be employed, and the amounts applied should preferably vary regularly with the paper machine speed, and be adjustable to the various grades and weights of paper run.

As will be apparent this method of sizing may be combined with other methods for sizing papers filled with alkaline filler, for example those disclosed in my above mentioned two copending applications. At any rate if the machine broke from my process be reintroduced into the fibrous mix from which \the paper is made, e. g. in the beater, the addition of a restoring agent or size precipitant, particularly an acidic material such as alum, just prior to web formation is desirable to control the foam resulting from the deterioration or destruction of the sizing in the broke by the alkaline filler. i

I have found that it is possible to precipitate the sizing, particularly in the presence ,of a colloid, and apply the precipitated sizing to the web instead of actually precipitating the sizing in the web, but such procedure eems to take more sizing in certain instances. It is also possible to apply the size and/or size precipitant to the web as it is in the process of formation on the web forming device, preferably after the fibres have been substantially positioned. But whereas I con sider such methods to fall within the scope of my invention I do not, however, consider them preferable procedures when my invention is employed on Fourdrinier machines, owing to the fact that. the addition of size and size precipitant or precipitated sizing at such point has a tendency to inter! e with the proper sheet formation.

I hav found at times that it is desirable to apply the size and/or size precipitant to both sides of the web instead of only to one side. I have found that in certain cases this assists in uniformly distributing the sizing throughout the sheet, particularly where the solutions are applied by means of rolls.

I may apply either the size orthe alum solution to. the web first, but, I prefer to apply the size first. v I c In certain cases, particularly where the presence of foam is not a serious detriment, the size may be, introduced into the mix prior to the web- --forming device, in which case only the size precipitant need-be applied at the web. Likewise the procedure may be reversed, applying therprecipitant to the mix just prior to the web-forming device and size to the web, but this latter procedure in general requires more preciptant. However, in either of these cases the precipitation actually takes place in the web.

The size I prefer 'to' use is rosin size and my preferredprecipitant is alum. Instead of rosin size I may use any other sizing agent, preferably one precipitable by a size precipitant, as such precipitated sizes, if employed in the usual manner in the beater, are deteriorated if not completely destroyed by alkaline filler in a similar manner to precipitated rosin sizing. Instead of alum as a size precipitant I may use with a measure of success other acidic material such as sulphuric acid, or other metallic salts such as zinc sulphate or sodium bisulphate, or other compounds of aluminum such as aluminum chloride or the like, but I prefer alum.

Where I use the term solution", in respect to size, I mean t include not only those cases in which the size ay be present as a true solution, but also those cases where it may be present in whole or in part as a suspension and/or emulsion.

Where I use the term rosin size herein I mean size made by any process from any natural or synthetic resin acid or acids, regardless of the exact composition of the productor the varying composition which different samples may possess.

By the term alkaline filler I mean substantially water insoluble filler which when agitated in contact with freshly boiled distilled water, say for an hour, will impart a pH value to such water greater than 7.0, that is, which will be on the alkaline side of the neutral point. Among fillers in this group may be mentioned calcium carbonate, of which lime mud from the causticizing process is one form; calcium carbonate magnesium basic carbonate employed in the paper disclosed in my United- States Patent No. 1,595,416, issued August 10, 1926; calcium carbonate magnesium hydroxide disclosed by my United States. Patent No. 1,415,391, issued May 9, 1922; and other substantially water insoluble normal or basic carbonates of alkaline earth metals, (which expression is herein intended to include magnesium), or compounds, double salts, or other physically associated mixtures of these with one or more other acid soluble materials of a substantially water insoluble nature. By the term alkaline filler" I also intend to include fibrous material and/or other material such as paper coating constituents 120 or the like containing one or more compounds of the character referred to, such as old papers" or similar papers, broke, or the like.

Where in the claims I use the word we I means to include not only the already formed 5 web, after it has left the web-forming device, but also the forming web as it exists at any point on the web-forming device. v

When I use the word paper herein, I use'it. in the broad sense to include products of. manufacture of all types and of all weights and thicknesses, which contain as an essential constituent a considerable amount of prepared fibre and which are capable of being produced on a Fourdrinier, cylinder, or other forming, felting, shaping or'. molding machine.

' While I have described in detail the preferred embodiment of my invention, it is to be understood that the details of procedure, the proportions of ingredients, and the arrangement of steps may be widely varied without departing from the the spirit of my invention or the scope of the sub- J. ined claims.

claim:

1. The method of manufacturing sized paper filled with alkaline filler comprising the inclusion in a fibrous web containing alkaline filler of substantially water-insoluble precipitated sizing material, said inclusion taking place subsequent to the point of delivery to a web-forming device 2. The method of manufacturing sized paperfilled with alkaline filler comprising effecting the precipitation of size in a fibrous web containing alkaline filler to form substantially water-insoluble sizing, and subsequently dryingsaid web.

I I 3 size precipitant to the papermaking mix just prior to web formation.

14. The cyclic procpdure in a method for manufacturing sized yp'aper filled with alkaline filler comprising the inclusion in a fibrous web containing alkaline filler of precipitated sizing material/ said inclusion taking place subsequent to 3. The method of manufacturing sized pap r/the point of delivery to a web-forming device of filled with alkaline filler comprising treating a fibrous web containing alkaline filler with size and size precipitant to form substantially waterinsoluble sizing, and subsequently drying said treated web.

4. The method of manufacturing sized paper filled. with alkaline filler comprising treating a fibrous web containing alkaline filler with rosin size and size precipitant, and subsequently drying said treated web. A

5. The method of manufacturing sized paper filled with alkaline filler comprising treating a fibrous web containing alkaline filler with rosin size and acidic material, and subsequently drying said treated web.

6. The method of manufacturing sized paper .filled with alkaline filler comprising treating a fibrous web containing alkaline filler with rosin size and metallic salt, and subsequently drying said treated web. v

'7. The method of manufacturing sized paper filled with alkaline filler comprising treating a fibrous web containing alkaline filler with rosin size and alum, and subsequently dryingsaid treated web.

'8. The method of manufacturing sized paper filled with alkaline filler comprising treating a wet fibrous web containing alkaline filler with size and size precipitan't to form substantially waterinsoluble sizing, and .subsequently drying said treated web.

9,. The method of manufacturing sized paper filled with alkaline filler comprising treating a wet fibrous web containing alkaline filler with rosin size and size precipitant, and subsequently drying said treated web.-

10. The method of manufacturing sized paper filled with alkaline filler comprising treating a wet fibrous web containing alkaline filler with rosin size and aci '0 material, 'andsubsequently drying said treate web.

11. The method of manufacturing sized paper filled with alkaline filler comprising treating a wet fibrous web containing alkaline filler with rosin size and alum, and subsequently drying said treated web.

12. The cyclic procedurein a method for manufacturing sized paper filled with alkaline filler comprising the inclusion in a fibrous web containing alkaline filler of precipitated sizingma terial, said inclusion taking place subsequent to the point of delivery to a web-forming device of the fibrous mix from which'said web is formed;- the returning of broke from the paper making op- ,mrstion to the heater, and the addition of a the fibrous mix from which said web is formed, the returning ofibroke from the paper making operation to the beater, and the addition of acidic material to the paper making 'mix just prior to web formation. \p v 15. The cyclic procedure in a method for manufacturing .sized paper filled with alkaline filler comprising the inclusion in a fibrous web'containing alkaline filler of precipitated sizing ma-' terial, said inclusion taking place subsequent to the point of delivery to a web-forming device of the fibrous mix from which said web is formed,

vthe returning of broke from the paper making op-' eration to the beater, andthe addition of alum to the papermaking mix just prior to web formation. a

16. The cyclic procedure in a method for manufacturing sized paper filled with alkaline filler comprising treating a fibrous web' containing alkaline filler with size and size precipitant,'returning broke from the paper making operation to the fibrous mix prior tov web formation, and adding .a size precipitant to the mix just prior to web formation.

17. The cyclic procedure in a method for manufacturing sized paper filled with alkaline filler comprising. treating a fibrous web containing al- 19. The cyclic procedure in a method for man-1 ufacturing sized-paper filled with alkaline filler comprising treating a fibrous web containing al- 'kaline filler with rosin size and alum, returning broke from the paper making operation to the fibrous mix prior to web'formation, and adding 3 alum to the mix just prior to web formation. Y

20. The cyclic procedure in a method for manufacturing sized paper filled with alkaline filler comprising treating a fibrous web containing alkaline filler with rosin size and alum, returning broke from'the paper making operation to the heater, and adding alum to the paper making mix just prior to web formation.

21. The method of manufacturing sized paperfilled with alkaline filler comprising the inclusion in a fibrous web containing alkalinev filler comprising calcium carbonate of substantially water-insoluble precipitated sizing material, said.

inclusion taking place subsequent to the point of delivery to a web-forming device of the fi-' brous mix from which said web is formed, and the subsequent drying of said web.

22. The method of manufacturing sized paper filled with alkaline filler comprising the inclusion in a fibrous web containing alkaline'filler. comprising calcium carbonate and magnesium compound of substantially water-insoluble precipitated sizing material, said inclusion taking place subsequent to the point of delivery to awebforming device of the fibrous mix from which said droxide of substantially water-inso1uble'precipi-.

tated sizing material, said inclusion taking place subsequent to the point of delivery to a webforming device of the fibrous mix from which said web is formed, and the subsequent drying of said web.

24. The step in a method of manufacturing sized paper filled with alkaline filler comprising the application to a fibrous web containing alkaline filler of precipitated sizing material subsequent to the point where said web leaves the web- 'forming device.

25. The step in a method of manufacturing sized paper filled with alkaline filler comprising the application to a fibrous web containing alkaline filler of substantially water-insoluble sizing compound containing metallic radical.

26. The stepin a method of manufacturing sized paper filled with alkaline filler comprising the application to a fibrous web containing alkaline filler resinate.

2'7. The steps in a method of manufacturing sized paper filled with alkaline filler comprising applying sizing agent in aqueous solution to a fibrous web containing alkaline filler, and then effecting the conversion of said applied sizing agent into a substantially water-inso1uble form. 28. The steps in a method of manufacturin sized paper filled with alkaline filler comprising applying an aqueous solution of resin size to a fibrous web containing alkaline filler, and then eifecting the conversion of said applied rosin size into a substantially water-insoluble form.

'29.'The step in a method of manufacturing sized paper filled with alkaline filler comprising effecting the precipitation of size in a fibrous web containing alkaline filler to form substantially water insoluble sizing.

30. In a method of manufacturing paper filled with alkaline filler wherein sizing agent is emof substantially water-insoluble ployed, wherein material is applied to a web concapable of imparting sizing effect to said web, that step comprising the applicationto said web of said acidic material.v

32. In a method of manufacturing paper filled with alkaline filler wherein sizing agent is employed, wherein material is applied to a web containing alkaline filler, and wherein there is produced by the action of metallic salt applied to said web substantially water-insoluble substance -capable of imparting sizing effect to said web, that step comprising the application to said web of said metallic salt.

33. In a method of manufacturing paper filled with alkaline filler wherein sizing agent is employed, whereinmaterial is applied to a web containing alkaline filler, and wherein there is produced-by the action of alum applied to said web substantially water-insoluble substance capable of imparting sizing effect to said web, that step comprising the application to said web of said alum.

34. In a method of manufacturing paper filled with alkaline filler, the steps comprising prepar= ing a fibrous mix, incorporating size precipitant as an ingredient of said mix, forming a web from said mix, and applying sizing agent to said web to form substantially water-insoluble sizing.

35. In a method of manufacturing paper filled. with alkaline filler, the'steps comprising preparing a fibrous mix, incorporating metallic salt as an ingredient of said mix, forming a web from said mix, and applying sizing agent to said web.

36. In a method of manufacturing paper filled with alkaline filler, the steps comprising preparing a fibrous mix, incorporating alum as an ingredient of said mix, "forming a web from said mix, and applying sizing agent to said web.

37. In a method of manufacturing paper filled with alkaline filler, the steps comprising preparing a fibrous mix, incorporating size precipitant as an ingredient of said mix, forming a web from said mix, and applying rosin size to said web.

38. In a method of manufacturing paper filled with alkaline filler, the steps comprising preparing a fibrous mix, incorporating alum as an ingre- 'dient of said 'mix, forming a web from said mix, and applying rosin size to said web.

39. In a method of sizing paper filled with alkaline filler wherein a fibrous mix is run off on a web-forming device, the improvement comprising incorporating sizing in the fibrous mix, and thereafter imparting additional sizing to one side of the web formed therefrom.

40. In a method of sizing paper filled with alkaline filler wherein a fibrous mix is run off on a Web forming device, the improvement comprising incorporating sizing in the fibrous mix by means of size and acidic material, and thereafter imparting additional sizing to the web formed from said mix.

41. Filled paper comprising fibrous material, alkaline filler, sizing incorporated therein, and 135 additional sizing on one side thereof.

42. Filled paper comprising fibrous material, alkaline filler, sizing precipitated by acidic material incorporated therein, and additional sizing on the surface thereof.

. HAROLD ROBERT RAFTON. 

